Preparefor themeltdown: Conservation groups make warning about global warming
November 30, 2005
Global warming could affect Tahoe’s environment in several ways, including the lake’s famed clarity, scientists say, prompting at least one conservation group to warn planners to prepare for the changes.
“We need to be planning now how to adapt to less snow, more fire, and many other changes,” said Joan Clayburgh, Sierra Nevada Alliance executive director.
Several signs of global warming are evident in the Sierra Nevada today.
Average temperatures in Tahoe have risen more than 2 degrees, spring snowmelt into the American River happens a week earlier than in the 1950s, and northern Sierra snowpack is already decreasing, according to several recent studies by scientists at Scripps Institute of Oceanography in San Diego and the U.S. Geological Survey.
More rain and less snow is falling throughout the West, according to an article in September’s edition of Nature Magazine, a premier scientific journal.
And Lake Tahoe’s water is almost a whole degree warmer than it was 30 years ago, according to UC Davis researchers.
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“Micro-climate in Tahoe basin has warmed with the lake and it means the snow will not last as long,” said Charles Goldman, scientist with UC Davis. “There might be more snow, but it might not last as long.”
Goldman was the first to point out 40 years ago that Lake Tahoe could be losing clarity. Warmer water will encourage algae growth, he said, which is thought to be half of Tahoe’s clarity problem.
Rain means erosion
Global warming could also impact Lake Tahoe’s clarity, said Dettinger, by increasing rain and erosion.
If more rain and less snow falls, that means more water flowing down the mountains at once, more soil erosion, and increased chance of flooding, Dettinger said. The worst thing is when rain falls on snow, melting it and creating more flowing water than gradual snowmelt.
The alliance predicts warming temperatures will affect river systems, forests, fisheries, flood control and development. They’ve prepared a climate change “tool kit” for members suggesting specific ideas for managing the resources of the Sierra. More information is available at http://www.sierranevadaalliance.org
John Friedrich, program manager at the League to Save Lake Tahoe, a member of the alliance, said global warming has not been a big part of decision making at Tahoe, but it should be.
Last week, the Tahoe Daily Tribune reported on an upcoming study on global warming’s affects on California’s economy. The report will include predictions that Sierra’s snowpack could decline significantly, which could have implications for the ski industry.
Heavenly Mountain Resort and Tahoe’s planning agency should be considering long-term predictions for decreased snowpack, Friedrich said. That will mean more snowmaking and more competition for water resources.
Plans are in the works to expand Heavenly’s trail acreage by 11 percent. By infilling within their boundaries, Heavenly would add 67 more acres of trails on top of it 745 existing acres.
Andrew Strain, vice president of planning and government affairs for Heavenly, said the resort is not planning for global warming in these current changes because they were approved under the 1996 master plan.
But thre resort does take climate change seriously, he said.
“We want more winter and not less winter,” Strain said.
Friedrich pointed out that pollution from cars is not only a major contributor to global warming, but also Lake Tahoe’s declining clarity.
“It’s a double incentive to get serious about the need to reduce auto emissions and produce alternative transportation,” Friedrich said.An estimated 59 percent of the nitrogen going into Lake Tahoe comes from air pollution, according to studies by the Tahoe Research Group. Most of that nitrogen pollution comes from cars in the Lake Tahoe Basin, scientists believe. Nitrogen is a nutrient that feeds algae growth.
The League – which issues those ubiquitous “Keep Tahoe Blue” bumper stickers – has been a consistent critic of so-called mitigation strategies used by the Tahoe Regional Planning Agency to attempt to offset the affects of development in the region, including air pollution from cars.
For instance, with a given that more buildings means more cars, developers are charged an air pollution mitigation fee that goes toward mass transit.
Tit for tat?
The mitigation fees do not adequately address the problems of increased development, Friedrich said.
“Allowing development with flawed mitigation is put out as this win-win for everyone,” Friedrich said. “In reality it’s at expense of the lake. They need to take a harder look at whether the project should be approved in the first place which then requires a stricter view on what kind of development should be permitted.
“You can’t have everything, something has to give.”
The TRPA acknowledges its current mitigation system has problems and is looking to improve it as more information becomes available through the planning process for Tahoe’s future, called Pathway 2007, said spokeswoman Julie Regan.
Meanwhile, TRPA must operate under guidelines of the most current regional plan.
“We are not approving development that wasn’t acceptable under that plan, and the League was very much involved in the consensus process of the ’80s,” Regan said.
Lahontan Water Board, which regulates water quality at Lake Tahoe, is considering global warming in its models, but cannot make rules based on those because of uncertainty of how things may turn out, said environmental scientist Dave Roberts.
It is certain things will change, but it’s not certain how they will change, he said.
“Our simulations are based on what happened in the past 40 years, not what will happen in the next 40 years,” Roberts said.
Global warming signs in the Sierra
— Average temperatures in Tahoe up more than 2 degrees.
— Spring snowmelt into the American River a week earlier than 1950s.
— Northern Sierra snowpack measurably decreasing.
— More rain and less snow falling throughout the West.
— Lake Tahoe’s water is almost 1 degree warmer than 30 years ago.
Sources: Scripps Institute of Oceanography, U.S. Geological Survey, and UC Davis.